title: Recurrent urolithiasis following parathyroidectomy for primary hyperparathyroidism.
abstract: BACKGROUND
  The effect of parathyroidectomy on the incidence of recurrent stone formation is uncertain. We aimed to compare the biochemistry and recurrence rate of urolithiasis in patients with primary hyperparathyroidism (pHPT) and stone formation (SF) and non-stone formation (NSF) with idiopathic stone formers (ISF).
  
  
  METHODS
  Patients with pHPT and SF (Group 1) were identified from a prospective database. pHPT patients and NSF (Group 2) and ISFs (Group 3) were randomly selected from respective databases to form three equal groups. Preoperative and postoperative biochemical data were analysed and recurrent urolithiasis diagnosed if present on follow-up radiology. Out-of-area patients were asked about recurrence via telephone.
  
  
  RESULTS
  From July 2002 to October 2011, 640 patients had parathyroidectomy for pHPT. Of these, 66 (10.3%) had a history of renal colic; one was lost to follow-up. Patient demographics were similar across all three groups. Three months post-parathyroidectomy, Groups 1 and 2 had significantly reduced serum calcium concentrations (p<0.01). Group 1 had lower urinary calcium excretion after parathyroidectomy (p<0.01), but estimated glomerular filtration rate did not change following surgery. During median follow-up of 4.33 years (0.25-9 years) in Groups 1 and 2 and 5.08 years (0.810-8 years) in Group 3, one patient (1.5%) in Group 1 and 16 patients (25%) in Group 3 had recurrent urolithiasis (p<0.01). No Group 2 patients developed stones.
  
  
  CONCLUSIONS
  Curative parathyroidectomy confers a low recurrence rate for urolithiasis, but does not prevent recurrence in all patients. Further research should aim to identify the risk factors for continued SF in these patients.
authors.affiliation: Department of Endocrine Surgery, University Hospital of Wales, Cardiff, UK.
authors.forename: C
authors.initials: C
authors.lastname: Rowlands
authors.forename: A
authors.initials: A
authors.lastname: Zyada
authors.forename: S
authors.initials: S
authors.lastname: Zouwail
authors.forename: H
authors.initials: H
authors.lastname: Joshi
authors.forename: M J
authors.initials: MJ
authors.lastname: Stechman
authors.forename: D M
authors.initials: DM
authors.lastname: Scott-Coombes
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000601:surgery*; D007669:Kidney Calculi / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016105:Parathyroidectomy; D011446:Prospective Studies; D012008:Recurrence; D055815:Young Adult
chemical_list: D015415:Biomarkers